Leak Prevention – Underground Storage Tanks

Underground Storage Tank (UST) Program – Chapter 16 Rewrite

The Draft Chapter 16 of Division 3 of Title 23 of the California Code of Regulations Rewrite

The State Water Board is drafting amendments to chapter 16 of division 3 of title 23 of the California Code of Regulations (Chapter 16 Rewrite) to update and modernize the regulations, including amendments necessary to implement amendments to applicable provisions of the Health and Safety Code.

Pursuant to Health and Safety Code section 25292.05, all single-walled USTs must be permanently closed on or before December 31, 2025.  The Chapter 16 Rewrite includes deleting all provisions relating to single-walled USTs as these systems will be prohibited starting January 1, 2026.  For additional information on single-walled UST closure requirements, please refer to the Single-Walled UST Webpage

It is expected that the amendments to the UST Regulations will be effective January 1, 2026.  The public will have an opportunity to comment on the Chapter 16 Rewrite through the formal rulemaking process beginning in the fall of 2024.


  Staying Connected

Subscribe to the underground storage tank (UST) "Program Requirements and Guidance" mailing list to receive direct notification about the upcoming Chapter 16 Rewrite.

  Public Participation

State Water Board staff hosted a focus workgroup over Microsoft Teams during the fall of 2022 consisting of State Water Board staff, UST regulators, and select representatives from the UST regulated community.  In addition, State Water Board staff held three public informational webinars on September 14, 2023, September 19, 2023, and September 27, 2023.  Participants included UST owners and operators, UST regulators, contractors, component manufacturers, and other representatives from the UST regulated community to review and ask questions related to the proposed changes in the Chapter 16 Rewrite.  These webinars, which can be accessed below, are not part of the formal rulemaking process.

The public will have an opportunity to submit comments on the Chapter 16 Rewrite during the formal rulemaking process in the fall of 2024.  Members of the public will be able to submit questions and comments related to the regulations as part of this formal process.  Additional guidance will be provided at that time. 

Informational Webinars on the Upcoming Chapter 16 Rewrite

Informational Webinar

सूचनात्मक वेबिनार

Seminario Web Informativo

Contact Us

Have a Question? Contact the Program.